Momentum-interaction type fluidic devices

ABSTRACT

In order to permit a fluidic amplifier of the momentuminteraction type to receive, in addition to its main control by a pair of transverse control jets, a secondary control input, its power input is arranged in the form of two jet nozzles 2A and 2B respectively aligned with the output branches at the two sides of a splitter wedge 15, thus permitting a pressure difference representing the secondary control input to be applied between the two power-input branches 1A and 1B.

i i Umted States Patent 1 1 1111 3,744,525 Davies July 10, 1973 MOMENTUM-INTERACTION TYPE 3,238,959 3/1966 Bowles 137 815 FLUIDIC DEVICES 3,272,212 9/1966 Bowles... 137/815 3,340,885 9/1967 Bauer 137/815 [75] Inventor: Guy Edward Davies, Fareham, 3,457,934 7/1969 Kinner... 137/815 England 3,570,515 3/1971 Kinner 137/815 3,500,852 3/1970 Bauer 137/815 [73] Asslgnee: The Hesse! clml'any 3,530,869 9/1970 Di Camillo 137/815 "ford, England 3,444,87 5 1969 Sieracki et a1 137/815 2, Richards [21] Appl' 68365 Primary Examiner-Samuel Scott Attorney-Blum, Moscovitz, Friedman and Kaplan [301 Foreign Application Priority Data Sept. 10, 1969 Great Britain 44,707/69 [57] ABSTRACT In order to permit a fluidic amplifier of the momentum- 'i interaction type to receive, in addition to its main con- 5 Fie'ld 137/81 5 trol by a pair of transverse control jets, a secondary control input, its power input is arranged in the form of two jet nozzles 2A and 28 respectively aligned with the [56] References cued output branches at the two sides of asplitter wedge 15, UNITED STATES PATENTS thus permitting a pressure difference representing the 3,331,379 7/1967 Bowles 137/815 secondary control input to be applied between the two SOWCI'S... powexuinput branches and 1B 3,240,220 3/1966 Jones 137/81.5 3,502,093 3/ 1970 Leskiewi 137/815 2 Claims, 4 Drawing Figures MOMENTUM-INTERACTION TYPE FLUIDIC DEVICES This invention relates to the control of momentuminteraction type fluidic devices, more particularly fluidic amplifiers, and has for an object to provide improved devices of this kind which lend themselves to the introduction of a secondary control unit. The facility of such secondary input is in many cases desirable, for example to introduce a time-differential dependent function of a primary input to achieve a certain degree of transient or dynamic response. It is possible, and has already been proposed, to achieve this by providing, in addition to the two control-input connections of a normal momentum-interaction type amplifier, a pair of further control-input connections while attempting to keep both pairs of control input connections as close as possible to the power-input jet efflux in order to maintain good performance; it was however, difficult to achieve this while maintaining reasonable separation between adjacent channels and nozzles, and manufacture also became somewhat complicated.

According to the present invention a secondary control facility is provided by supplementing or replacing momentum-interaction type fludic device, more particularly of a fluidic amplifier by an arrangement having two separate input-flow passages arranged to produce two input jets inclined in opposite directions to the longitudinal axis of the device thus permitting a secondary input to be applied as a pressure difference between these two inlets, the arrangement being such that the jets from the two input passages combine to form a single jet which in the absence of a secondary input extends along the longitudinal axis of the device, i.e., the axis, in which in a normal amplifier, the power jet is arranged to operate.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which FIG. 1 shows the arrangement of the passages in a customary momentum-interaction proportional fluidic amplifier having a single pair of control-input connections,

FIG. 2 similarly illustrates double-input momentuminteraction amplifier as'previously proposed for the provision of a secondary-input facility.

FIG. 3 illustrates one form of improved amplifier according to thepresentinvention, which while simpler in construction provides facilities equivalent to those provided by the amplifier shown in FIG. 2,

FIG. 4 illustrates a fluidic arrangement in which an amplifier as shown in FIG. 3 is combined with transient-bias means arranged to produce the secondary input.

Referring first to FIG. 1, a fluidic amplifier of the momentum-interaction type has a power-input connection 1 leading to a power nozzle 2. This nozzle is adapted to produce a power jet of operating fluid and is normally so arranged that this power jet will produce equal pressures and/or equal rates of flow at two output ports 3 and 4 which are inclined, symmetrically to each other, in opposite directions to the axis of the jet produced by the nozzle 2 and separated from each other by a splitter portion 15. Arranged also symmetrically to each other, but at a greater angle to the axis of the jet, are two vent outlets 5 and 6 through which the excess fluid of the jet over the amount passing through the output ports 3 and 4can flow off. The amplifier is further provided with a pair of control-input nozzles 7 and 8. These extend at right angles to the axis of the power jet, and a control-input pressure difference can be applied between their inlets 9 and 10 respectively to pro duce a control jet transverse to the power jet. This control jet will operate to divert the power jet so as to increase the amount of flow and/or the pressure in output port 3 over that in output port 4 or vice versa, according to the direction of the pressure difference producing the control jet. In the double-input proportional fluidic amplifier illustrated in FIG. 2 the same reference numerals as for FIG. 1 are employed to indicate corresponding elements. In order to permit the application of a further or secondary control, a second pair of control-input ports 11, 12 having input connections 13 and 14 to which a secondary control-pressure difference can be applied, are arranged between the main control ports 7, 8 and the vents 5, 6. It will be seen that in this construction,'in order to get a reasonable approach to ideal action conditions, the direction of the main control nozzles 7 and 8 had to be changed somewhat to one side of a line at right angles to the main power jet, the secondary control ports being offset from this line by the same amount in the opposite direction.

FIG. 3 illustrates an amplifier according to the'present invention. The same reference numerals as in FIG. 1 have again been employed for corresponding parts, and it will be readily appreciated that it was possible to maintain most elements in the same form and mutual arrangement as in the single-control amplifier of FIG. 1. The power-jet inlet 1 and power-jet nozzle 2, which extend along the longitudinal axis of the device of FIG. 1, have, however, been replaced by a pair of inlets 1A and 1B each provided with a power jet nozzle 2A and 2B respectively, these two nozzles being inclined oppositely and symmetrically to the longitudinal axis of the device, In the illustrated preferred form they are in substantial respective alignment with the two outlets 4 and 3 of the device. When both inlets 1A and 1B are sup-- plied with fluid under the same pressure, the jets formed by the nozzles 2A and 28 will combine to form a single jet flowing along the longitudinal axis of the device, while when, in order to achieve a secondary control, a pressure difference is applied between the inlets 1A and 1B, the combined jet formed by combination of the jets issuing from the nozzles 2A and 28 will be inclined, in accordance with the amount and sign of this pressure difference, towards one or the other of the outlets 3 and 4 which are separated by the splitter 15 v of the amplifier.

In FIG. 4 the device of FIG. 3 is shown connected to means for deriving from a main-control pressure difference, a transient bias in the form of a pressure difference, which is applied between the inlets 1A and 13 as a secondary input. The same reference numerals as in FIG. 3 have been used for the elements of the amplifier of that Figure, the whole amplifier having the reference number 18. To provide the power input with a transient bias, a power-input pressure source 17 is connected to the input end 1A of one of the power-jet nozzles 2A and this input end 1A is also connected to a reservoir 20 via a venturi 21, while the input end 18 of the other power-jet nozzle 28 is arranged at the throat of the venturi 21. Of the main control nozzles 7, 8, the one nozzle 7 has been connected at 10 to a point under reference pressure, while the same pressure source 17 which feeds the power inlet 1A and whose pressure is presumed to be variable, is applied, via a so-called planar jet collector 16 to control input 9 leading to the other main control nozzle 8. The jet collector chamber 16 is vented to the environmental atmosphere, so as to cause the pressure difference between the two control inlets 9 and to be affected, in a non-linear fashion, by the environmental atmospheric pressure, as well as by the pressure of the input source 17. The outputs 3 and 4 are shown connected to the control-input nozzles 7b, 8b of a further amplifier stage 18A which may be constructed as shown in FIG. 1. The system illustrated in FIG. 4 may, for example, be employed for the control of the compressor-intake vanes of a gas-turbine engine in a manner which is explained in more detail in our copending application corresponding to British Pat. application No. 44708/69.

It should be appreciated that the invention is not limited to all the features of the particular embodiments described. Thus in the embodiment of FIG. 4 the jet collector chamber 16, instead of being vented to the atmosphere, may communicate with some other reference pressure, which may be variable.

What we claim is:

1. A pure-fluidic device for the production of a continuously variable output, which comprises in combination: a body formed with an inter-action chamber, with two power-jet nozzles leading into said chamber with their axes intersecting at an acute angle to produce two component jets which join to form a composite power jet whose angular direction varies continuously, within the plane defined by the two component jets, between the respective directions of the two component jets ac.- cording to the ratio of the respective flow rates in the two said nozzles, with two power-jet inlet ducts, one for each nozzle, for respective connection of the said nozzles to two fluid sources of independently variable pressures, with two output passages extending from the inter-action chamber at points which are respectively in the path of such composite power jet at two different angular directions thereof in said plane, and with a jet splitter forming a wedge that separates the two said output passages at their ends connected to the interaction chamber, and in which said body is further provided with a control-input passage leading into the inter-action chamber to produce a control jet for interaction with the composite jet within the plane of directional variation of said composite jet, the two power-jet nozzles being so arranged in relation to each other and to said output passages that, when equal pressures are applied to said two power-jet inlet ducts, the said composite power jet will, in the absence of such control jet, extend in at least approximate alignment with the centre line of the jet-splitter wedge; and a fluid-flow device provided with tappings and constructed to produce at said tappings a pressure difference which is a function of the rate of flow in said fluid-flow device, the two said power-jet inlet ducts being respectively connected to said tappings.

2. A fluidic device as claimed in claim 1, which includes a planar jet collector attached to the said control input passage for connection to a control-input pressure. 

1. A pure-fluidic device for the production of a continuously variable output, which comprises in combination: a body formed with an inter-action chamber, with two power-jet nozzles leading into said chamber with their axes intersecting at an acute angle to produce two component jets which join to form a composite power jet whose angular direction varies continuously, within the plane defined by the two component jets, between the respective directions of the two component jets according to the ratio of the respective flow rates in the two said nozzles, with two power-jet inlet ducts, one for each nozzle, for respective connection of the said nozzles to two fluid sources of independently variable pressures, with two output passages extending from the inter-action chamber at points which are respectively in the path of such composite power jet at two different angular directions thereof in said plane, and with a jet splitter forming a wedge that separates the two said output passages at their ends connected to the inter-action chamber, and in which said body is further provided with a control-input passage leading into the inter-action chamber to produce a control jet for inter-action with the composite jet within the plane of directional variation of said composite jet, the two power-jet nozzles being so arranged in relation to each other and to said output passages that, when equal pressures are applied to said two power-jet inlet ducts, the said composite power jet will, in the absence of such control jet, extend in at least approximate alignment with the centre line of the jet-splitter wedge; and a fluid-flow device provided with tappings and constructed to produce at said tappings a pressure difference which is a function of the rate of flow in said fluid-flow device, the two said power-jet inlet ducts being respectively connected to said tappings.
 2. A fluidic device as claimed in claim 1, which includes a planar jet collector attached to the said control input passage for connection to a control-input pressure. 